rql #20111 implement relation paths [open]

With inspiration from http://www.w3.org/TR/sparql11-property-paths/ let's implement the equivalent in RQL.

Any X WHERE X is Ticket, X concerns P, P name "rql"

could be written as

Any X WHERE X is Ticket, X concerns/name "rql"

prioritynormal
typeenhancement
done in<not specified>
closed by<not specified>